1. Field of the Invention
The present invention relates to a transaxle provided with a power take-off (hereinafter, “PTO”) device for transmitting power from a transmission in the transaxle. In one embodiment, the transaxle is available to a four-wheel driving vehicle such as a utility vehicle, and the power take-off device is adapted for transmitting power to another transaxle.
2. Related Art
As disclosed in Japanese Laid-Open Gazette No. 2005-297673, there exists a well-known and conventional four-wheel drive vehicle. In the vehicle, a first transaxle is provided for driving two wheels at either the front or rear portion of the vehicle, and a second transaxle is provided for driving two wheels at the other portion of the vehicle. The first transaxle is provided with an input portion on one of right and left sides thereof, and is provided with a PTO shaft on the other of right and left sides thereof laterally opposite to the input portion. A prime mover is arranged between the first and second transaxles. A transmission such as a continuously variable transmission (CVT) is extended from the prime mover and is drivingly connected to the input portion of the first transaxle driven by the transmission. A power train is extended from the PTO shaft laterally opposite to the transmission with respect to the first transaxle, while being laterally offset from the prime mover, and is drivingly connected to an input portion of the second transaxle.
In the conventional power train between the PTO shaft of the first transaxle and the input portion of the second transaxle, a PTO casing incorporating a start element of the power train for receiving power from the PTO shaft is disposed to face the PTO shaft. The PTO casing is separate from the first transaxle, and is mounted to a vehicle frame. This arrangement of the PTO casing is convenient for ensuring flexibility in the direction of the power train extended from the PTO casing. For example, if the input portion of the second transaxle is lower than the PTO shaft, the PTO casing may be supported slantwise by the vehicle frame so as to extend the power train forwardly downward, as disclosed in the above reference. However, such a PTO casing is disadvantageous in minimization of the vehicle and in facilitation of mounting thereof. Further, the PTO shaft during rotation transmits undesirable vibration to the PTO casing so as to undesirably vibrate the vehicle frame.
It should be considered that the referenced PTO casing is mounted integrally on a transaxle housing of the first transaxle. However, while the first transaxle can be easily standardized, it is difficult to standardize the power take-off casing because it should be disposed or shaped considering the positional relation between the PTO shaft of the first transaxle and the input portion of the second transaxle. For example, if the PTO shaft is higher than the input portion of the second transaxle, the PTO casing having an input part for receiving power from the PTO shaft as high as the PTO shaft should be considered in arrangement or shape for transmitting power to the lower input portion of the second transaxle. The difficulty in standardization of the PTO casing hinders economization of the vehicle.